Glossary of Terms and Acronyms
| Acronym/Term | Meaning |
|---|---|
| AAR | Airport Arrival Rate or Airport Acceptance Rate |
| AFSS | Automated Flight Service Station (see Flight Service Station) |
| AGL | Above Ground Level |
| Aircraft Dispatcher (also referred to as just "dispatcher") | Person responsible for commercial flight planning. His/ her largest concerns are the safest route and landing alternate fuel requirements. He/she relies on either "company" or NWS TAFs. |
| Airport Arrival (or Acceptance) Rate (AAR) | The number of arriving aircraft that an airport or airspace can accept from the ARTCC per hour. The AAR is
used to calculate the desired interval between successive arrival aircraft. The arrival rate may change due
to a number of variables, including:
|
| Air Mass Thunderstorm | Generally, a thunderstorm not associated with a front or other type of synoptic-scale forcing mechanism. Air mass thunderstorms typically are associated with warm, humid air in the summer months; they develop during the afternoon in response to insolation, and dissipate rather quickly after sunset. They generally are less likely to be severe than other types of thunderstorms, but they still are capable of producing downbursts, brief heavy rain, and (in extreme cases) hail over 2 cm (3/4 inch) in diameter. Since all thunderstorms are associated with some type of forcing mechanism, synoptic-scale or otherwise, the existence of true air-mass thunderstorms is debatable. |
| Airport Surveillance Radar (ASR) | Approach control radar used to detect and display an aircraft's position in the terminal area. ASR provides range and azimuth information but does not provide elevation data. Coverage of the ASR can extend up to 100 km (60 miles). |
| Airport Traffic Control Tower | Terminal facility that uses air and ground communications, visual signaling and other devices to provide ATC services to aircraft operating in the vicinity of an airport or on the movement area. |
| Air Route Traffic Control Center (ARTCC) (also called "Center") | Provides air traffic control service to aircraft operating on IFR flight plans within controlled airspace and principally during the en route phase of flight. When equipment capabilities and controller workload permit, certain advisory/assistance services may be provided to VFR aircraft. There are 21 ARTCCs in the continental U.S. |
| Air Traffic Control (ATC) | A service operated by an appropriate authority to promote the safe, orderly, and expeditious flow of air traffic. |
| Air Traffic Control Specialist (ATCS) | One who provides for the safe, orderly, and expeditious flow of air traffic. Also referred to as "Air Traffic Specialist." In the FAA, an ATCS works in one of three specialized positions: (1) Terminal (Tower) Controller, (2), En Route Center Controller, or (3) Flight Service Station Controller. |
| Air Traffic Control System Command Center (ATCSCC) | The air traffic tactical operations facility responsible for monitoring and managing the flow of air traffic throughout the NAS, producing a safe, orderly, and expeditious flow of traffic while minimizing delays. Personnel at the ATCSCC routinely use TAFs for major airports across the country. |
| Area | All en route facilities are divided into “areas” of specialization. Areas are defined by their geographic location; i.e., north area, south area. Each of these areas may contain an arrival gate, a departure gate, or both. Each area is further divided into "sectors." |
| ARPT | Airport |
| Arrival Rate | See Airport Arrival Rate |
| ASR | Airport Surveillance Radar |
| ATC | Air Traffic Control |
| ATCS | Air Traffic Control Specialist |
| ATCSCC | Air Traffic Control System Command Center |
| ATCT | Airport Traffic Control Tower |
| Automated Flight Service Station (AFSS) | See Flight Service Station |
| Aviation Weather Center (AWC) | As a national center in the NWS, provides domestic and international data and advisory products to the aviation community. |
| AWC | Aviation Weather Center |
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| Braking Action | A report of conditions on the airport movement area providing a pilot with a degree/quality of braking that he/she might expect. Braking action is reported in terms of good, fair, poor, or nil. |
| CCFP | Collaborative Convective Forecast Product |
| Center |
See Air Route Traffic Control Center |
| Collaborative Convective Forecast Product (CCFP) | CCFP is a process that begins with an initial convective weather forecast for the next 2-6 hours being produced every 2 hours (except for the 05/6Z cycle) by the Aviation Weather Center in Kansas City. This forecast then evolves into a final product through collaboration by participating meteorologists at the Center Weather Service Units (CWSUs), various airlines, and the Aviation Weather Center. The CCFP is a critical input to the development of the Strategic Plan of Operation (SPO) teleconference. |
| Collaborative Decision Making (CDM) | A cooperative effort between the various components of aviation transportation, both government and industry, to exchange information for better decision making. The CCFP is an example of effective collaborative decision making. |
| Command Center | Air Traffic Control System Command Center (ATCSCC) |
| Control Sector | An airspace area of defined horizontal and vertical dimensions for which a controller or group of controllers has air traffic control responsibility, normally within an air route traffic control center (ARTCC) or an approach control facility. Sectors are established based on predominant traffic flows, altitude strata, and controller workload. Pilot communications during operations within a sector are normally maintained on discrete frequencies assigned to the sector. |
| Control Space | Term for entire volume of airspace that a particular air traffic control facility is responsible for. |
| Deicing | FAA regulations prohibit takeoff when contaminants such as frost, ice, or snow adhere to airplane wings, propellers, or control surfaces. These contaminants can change an airplane's performance characteristics. Deicing fluids are used to remove frost, ice, or snow. Anti-icing agents can be used to prevent accumulations for a certain period of time, called the "holdover time." |
| Direct User Access Terminal (System) (DUAT or DUATS) | FAA-approved vendors for filing flight plans and receiving weather briefings. DUAT or DUATS can be accessed by pilots with a current medical certificate toll-free in the 48 contiguous states via personal computer. Pilots can receive alpha-numeric preflight weather data and file domestic VFR and IFR flight plans. |
| DUAT(S) | Direct User Access Terminal (System) |
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| EFAS | En Route Flight Advisory Service |
| En Route Flight Advisory Service (EFAS) | A service specifically designed to provide en route aircraft with timely and meaningful weather advisories pertinent to the type of flight intended, route of flight, and altitude. It is also a central collection and distribution point for pilot-reported weather information (PIREP). |
| FAA |
Federal Aviation Administration (formerly Federal Aviation Authority) |
| Federal Aviation Administration (FAA) | Originally established by U.S. Congress as the Civil Aeronautics Authority, it was reorganized into the Administrator for Civil Aeronautics and the Civil Aeronautics Board before becoming the FAA |
| FL |
Flight Level |
| Flight Level (FL) | A level of constant atmospheric pressure related to a reference datum of 759.9 mm Hg (29.92 inches of mercury) starting at or above 5,500 m (18,000 feet, FL180). Each is stated in three digits that represent hundreds of feet. For example, flight level (FL) 250 represents a barometric altimeter indication of ~7,600 m (25,000 feet ); FL 255 is used for an altitude of 7,770 m (25,500 feet). Some countries specify flight level in meters, e.g., FL 5,400 or FL 10,800. |
| Flight Plan | Specified information relating to the intended flight of an aircraft that is filed orally or in writing with an FSS or an ATC facility |
| Flight Service Specialist | Performs the various duties required at a Flight Service Station. |
| Flight Service Station (FSS) | Air traffic facilities that provide pilot briefings, en route communications, VFR search and rescue services, assist lost aircraft and aircraft in emergency situations, relay ATC clearances, originate Notices to Airmen (NOTAMs), broadcast aviation weather and NAS information, receive and process IFR flight plans, and monitor NAVAIDs. In addition, at selected locations, FSSs provide En Route Flight Advisory Service (Flight Watch), take weather observations, issue airport advisories, and advise Customs and Immigration of transborder flights. |
| Flight Watch | Another name for En Route Flight Advisory Service (EFAS) |
| FSS | Flight Service Station |
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| GA | General Aviation |
| Gate |
Exchange point of air traffic between TRACON and ARTCC control space. Major airports usually have a set of arrival and departure gates. |
| GDP | Ground Delay Program |
| General Aviation (GA) | All civil aviation operations other than scheduled air services and non-scheduled air transport operations for remuneration or hire (ICAO). |
| Ground Delay Program (GDP) | A GDP is a TM process administered by the ATCSCC. GDPs are implemented to control air traffic volume to airports where the projected traffic demand is expected to exceed the airport's acceptance rate for a lengthy period of time. These periods are normally a result of the airport's acceptance rate being reduced for some reason (most commonly because of adverse weather such as low ceilings and visibility). Aircraft are held on the ground and assigned arrival slots in order to manage capacity and demand at a specific location and to limit airborne holding. |
| Ground Stop (GS) | Ground Stops require aircraft that meet specific criteria to remain on the ground. The criteria may be
airport-specific, airspace-specific, or equipment-specific(e.g., all departures to San Francisco, or all
departures entering Yorktown sector, or all Category I and II aircraft going to Charlotte). GSs normally
occur with little or no warning and are implemented for a number of reasons, the most common of which are:
|
| GS | Ground Stop |
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| Hold | Official term for a procedure that delays the arrival of an aircraft short of its destination in an effort to manage the sequencing of aircraft in the air or on the ground. Also called "spinning" or "parking," airborne holding of an aircraft is typically done by having the plane fly an elliptical pattern in a holding area until it is released for subsequent flight maneuvers. |
| Hub Airport | Many airlines operate on a "hub and spoke" concept, where flights generally start and end at a hub airport that acts as an operations base. This has been the traditional way to best manage equipment and human resources. Some airlines only have one hub airport, while others have three or four. For this reason, airports that are hubs tend to be busier than those that are not. Weather impacts at a hub airport can have significant effects on operations elsewhere in the NAS. There are 30 hub airports across the NAS, with the majority in the eastern half of the country. In the FAA, "hub" is commonly used to refer to a pacing airport. |
| ICAO | International Civil Aviation Organization |
| IFR | Instrument Flight Rules |
| ILS |
A precision instrument approach system normally consists
of the following electronic components and visual aids:
|
| ILS Categories | There are three categories of ILS that support similarly named categories of operation.
|
| Instrument Flight Rules (IFR) | Allow pilots to operate in weather conditions requiring reference to aircraft instruments, provided those conditions are within the operating envelope of the aircraft. To fly in IFR conditions, pilots must have an instrument rating, the aircraft must have the appropriate equipment, a flight plan must be filed, ATC clearance must be received, and two-way communications with ATC must be maintained. Any time an aircraft can not maintain VMC or is above 5500 m (18,000 ft) MSL, it must be flown under IFR. IFR is also a term used by pilots and controllers to indicate the type of flight plan. |
| Instrument (ILS) Approach Procedure |
A series of predetermined maneuvers by reference to flight instruments with specified protection from obstacles from the initial approach fix, or where applicable, from the beginning of a defined arrival route to a point from which a landing can be completed and thereafter, if a landing is not completed, to a position at which holding or en route obstacle clearance criteria apply. (from http://www.faa.gov/air_traffic/publications/atpubs/pcg/I.HTM ) |
| Instrument Landing System (ILS) | A ground-based precision approach system that provides course and vertical guidance to landing aircraft according to three ILS categories. |
| Integrated Terminal Weather System (ITWS) | Provides automated weather information and forecasts to air traffic controllers and supervisors. Its products require no meteorological interpretation to air traffic controllers, air traffic management systems, pilots, and airlines. |
| ITWS | Integrated Terminal Weather System |
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| LIFR | Low Instrument Flight Rules |
| LLWAS | Low Level Windshear Alert System |
| LO CIGS | Low Ceilings |
| Low Ceilings (LO CIGS) | Low clouds can create traffic delays as aircraft separation increases. |
| Low Instrument Flight Rules (LIFR) | Ceiling 60-120 m (200-400 ft) AGL and/or visibility 800 or 1,200 m (½ or ¾ mile). |
| Low Level Windshear Alert System (LLWAS) | System that measures wind speed and direction at sites around an airport terminal and then forecasts aviation impact parameters including windshear and microbursts. |
| LOW VIS | Low Visibility |
| Low Visibility (LOW VIS) | Low visibility can cause arrival and departure delays when aircraft separation increases for spacing and increased safety. |
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| Marginal Visual Flight Rules (MVFR) | A subcategory of VFR; ceilings 300 to 900 m (1,000 to 3,000 feet) AGL and/or visibility 4,800 to 8,000 m (3 to 5 miles) |
| MVFR | Marginal Visual Flight Rules |
| NAS | National Airspace System |
| National Airspace System (NAS) | The common network of U.S. airspace; air navigation facilities, equipment and services, airports or landing areas |
| National Transportation Safety Board | An independent Federal agency charged by Congress with investigating every civil aviation accident in the U.S. and significant accidents in the other modes of transportation and issuing safety recommendations aimed at preventing future accidents |
| NAVAID | Navigational Aid |
| Navigational Aid | A visual or electronic reference device that provides guidance information to aircraft |
| NOTAM | Notice to Airmen |
| Notice to Airmen (NOTAM) | A notice containing information (not known sufficiently in advance to publicize by other means) concerning the establishment, condition, or change in any component (facility, service, or procedure of, or hazard in the National Airspace System) the timely knowledge of which is essential to personnel concerned with flight operations |
| NTSB | National Transportation Safety Board |
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| PACE | Prototype Aviation Collaborative Effort |
| Pacing Airport | Due to their location and service as a hub to more than one airline, some airports (termed "pacing airports") can have a detrimental impact throughout the NAS when their operations are impacted by weather or non-weather events. The FAA has determined that the following are pacing airports: New York LaGuardia (LGA), Newark International (EWR), Chicago O'Hare International (ORD), San Francisco International (SFO), Boston Logan International (BOS), Philadelphia International (PHL), New York John F. Kennedy International (JFK), and Atlanta Hartsfield International (ATL). |
| Park | See Hold |
| Parallel Runways | Two or more runways at the same airport whose centerlines are parallel. In addition to runway number, parallel runways are designated as L (left) and R (right) or, if three parallel runways exist, L (left), C (center), and R (right). |
| Pilot Report (PIREP) | A non-routine, coded report of significant weather conditions (or lack thereof) along the route of flight. PIREP information includes cloud base and top height, indicated air temperature, weather, icing, turbulence, low-level wind shear, winds, location, flight level, and time. This information can be helpful in both the creation and validation of a TAF. |
| PIREP | Pilot Report |
| PPSST | Practically Perfect Site-Specific TAF |
| PP TAF | Practically Perfect TAF |
| Practically Perfect Site-Specific TAF (PPSST) | A TAF that concisely communicates the most airport-relevant, operationally essential forecast information in a customer-friendly, easy-to-use format. It addresses both ICAO TAF amendment and airport-specific criteria. |
| Practically Perfect TAF (PP TAF) | A TAF that concisely communicates the most operationally essential forecast information in a customer-friendly, easy-to-use format. It addresses ICAO TAF amendment criteria. |
| Precision/Non-Precision Approach | Approaches are classified as either precision or nonprecision, depending on the accuracy and capabilities of the navigational aids used. Precision approaches utilize both a localizer and glideslope information. Nonprecision approaches provide localizer information only. |
| Prototype Aviation Collaborative Effort (PACE) | Experiment designed to produce automated convective forecast products and intended to augment NWS services to the ATC community. |
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| Runway (RWY, RY) | A defined rectangular area prepared for the landing and takeoff run of aircraft along its length. Runways are normally numbered in relation to their magnetic direction rounded off to the nearest 10 degrees; e.g., Runway 1, Runway 25. |
| RWY | Runway |
| Runway Visual Range (RVR) | Runway Visual Range (RVR) is an instrumentally derived value that represents the horizontal distance a pilot will see down the runway from the approach end. RVR, in contrast to prevailing or runway visibility, is based on what a pilot in a moving aircraft should see looking down the runway. RVR is reported in hundreds of feet, so the values must be converted to statute miles if the visibility in statute miles is not reported. For more information on RVR, go to the following FAA web sites: How to Interpret Runway Visual Range and Runway Visual Range. |
| RVR | Runway Visual Range |
| RWY CONFIG | Runway Configuration |
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| Sector | A defined area of airspace usually designed around airways and/or jet routes. The sectors are irregular in shape and normally are sized to accommodate the general direction of traffic flow into the ARTCC. |
| Side-by | Slang for parallel runway operations |
| Spin | (Slang) See Hold |
| SPO | Strategic Plan of Operation |
| STMC |
Supervisory Traffic Management Coordinator |
| Strategic Plan of Operation (SPO) | Also referred to a Plan of Operation (PO). A collaboratively developed plan for short-term and long-term management of the NAS. Developed by the Strategic Planning Team after collaboration with the FAA, ARTCC Operations Manager, ATCSCC personnel, other FAA personnel, airline planners, international facilities, military, and general aviation system users. |
| Supervisory Traffic Management Coordinator (STMC) | The shift supervisor at the TMU who oversees the work of the TMCs |
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| TAF | Terminal Aerodrome Forecast |
| TDWR | Terminal Doppler Weather Radar |
| Terminal Aerodrome Forecast (TAF) | A concise statement of the expected meteorological conditions at an airport during a specified period (usually 24 hours). TAFs use the same weather code found in METAR weather reports. |
| Terminal Doppler Weather Radar (TDWR) | A 5-cm wavelength Doppler weather radar available at all large and most medium size airports. This information is included in the ITWS. |
| Terminal Forecast | See Terminal Aerodrome Forecast |
| Terminal Radar Approach Control Facility (TRACON) | A terminal ATC facility that uses radar and non-radar capabilities to provide approach control services to aircraft arriving, departing, or transiting airspace controlled by the facility. |
| TM |
Traffic Management, also an abbreviation for "time" |
| TMC |
Traffic Management Coordinator |
| TMI | Traffic Management Initiative |
| TMO |
Traffic Management Officer |
| TMP |
Traffic Management Program |
| TMU | Traffic Management Unit |
| TRACON | Terminal Radar Control Facility |
| Traffic Management Coordinator (TMC) | The person or persons who work in the TMU and manage the flow of air traffic in the Center's airspace |
| Traffic Management Initiative (TMI) | When TMCs coordinate with other facilities and implement some kind of traffic management program, it is called a TMI. |
| Traffic Management Officer (TMO) | The person in charge of the TMU |
| Traffic Management Program (TMP) | A special program implemented at airports that are expected to become busy enough that demand will exceed the capacity of the airport. Events such as the Indy 500 or the Super Bowl, or even unusually large amounts of traffic into some of the resorts like Aspen, Sun Valley, and Jackson during holiday periods, will prompt the need for a TMP. These programs are also called STMPs (Special Traffic Management Programs). They are initiated nationwide by the ATCSCC. Pilots are notified of these programs and are required to get special reservation times for arriving at the airport. |
| Traffic Management Unit (TMU) | Unit responsible for the management and balance of air traffic within the the ARTCC's control area in order to optimize air traffic flow through the NAS. The actions of the TMU are coordinated by the Command Center (ATCSCC). |
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| VFR | Visual Flight Rules |
| Visual Flight Rules (VFR) | Rules that govern the procedures for conducting flight under visual conditions. The term "VFR" is also used to indicate weather conditions that are equal to or greater than minimum VFR requirements. In addition, it is used by pilots and controllers to indicate the type of flight plan (i.e., VFR or IFR). An airport is "VFR" if the ceiling is at least 300 m (1,000 feet) AGL, and the visibility at least 4,800 m (3 statute miles). |
| Visual Meteorological Conditions (VMC) | Ceiling greater than 1,000 feet AGL and visibility greater than 4,800 m (3 statute miles). |
| VOL | Volume. Usually used to indicate that the volume of aircraft exceeds the airport's capacity. |
| VMC | Visual Meteorological Conditions |